Polyurethanes are a class of polymers having chains of organic units joined by carbamate linkages, but which can include other linkages as well. Polyurethanes can have a wide variety of physical properties. This is especially the case when polyurethanes are incorporated into block copolymers with other blocks, such as polyethers or polyesters. In some instances, certain blocks are hard or rigid (e.g., the polycarbamate portion) while others are soft and flexible (e.g., the polyester portion). Alteration of the chemical structure, size and/or frequency of these blocks in a polyurethane can allow for modification of the properties of the resin. These options can lead to resins having a wide array of different properties. Some of these resins can be thermosetting, while others can be thermoplastic.
Polyurethane foams can be used for a number of different applications. Polyurethane foams may be flexible or rigid, and can be used in a variety of different applications, including, but not limited to, use for foam insulation, use in packaging materials, and use in cushioning. Polyurethanes can also be used as elastomers. Polyurethane elastomers can be solid or porous, with representative applications including, but not limited to, textile fibers, coatings, sealants, adhesives, and resilient pads. Polyurethanes can also be used as thermosetting polymers. Representative applications of polyurethane thermosets include, but are not limited to, abrasion resistant wheels, mechanical parts, and structural materials.
In many cases, polyurethane synthesis occurs through the reaction of a dibasic acid or ester with a diisocyanate. The use of isocyanates presents certain environmental concerns. Thus, it may be desirable to make polyurethanes without the use of isocyanates.
Meanwhile, refining processes for natural oils (e.g., employing metathesis) can lead to compounds having carbon-chain lengths closer to those generally desired for chemical intermediates of specialty chemicals (e.g., about 9 to 15 carbon atoms). Thus, the refining of natural oils may, in many instances, provide a more chemically efficient and straightforward way to make certain monomers for use in making polymeric species. Further, because such compounds contain a certain degree of inherent functionality that is otherwise absent from petroleum-sourced materials, it may often be more desirable, if not cheaper, to use natural oils or their derivatives as a starting point for making certain compounds. Additionally, natural oils and their derivatives are generally sourced from renewable feedstocks. Thus, by using such starting materials, one can enjoy the concomitant advantage of developing useful chemical products without consuming limited supplies of petroleum.
Thus, there is a continuing need to discover novel monomers for making non-isocyanate polyurethanes, such as monomers derived from renewable sources.